Hi please review the attached patch.
Ok when bootstrap and test finish?
Thanks,
David
2011-04-07 Xinliang David Li <davi...@google.com>
* ipa-cp.c (ipcp_update_profiling): Correct
negative scale factor due to insane profile data.
Index: ipa-cp.c
===================================================================
--- ipa-cp.c (revision 171917)
+++ ipa-cp.c (working copy)
@@ -1113,6 +1113,29 @@ ipcp_update_profiling (void)
scale = ipcp_get_node_scale (orig_node);
node->count = orig_node->count * scale / REG_BR_PROB_BASE;
scale_complement = REG_BR_PROB_BASE - scale;
+
+ /* Negative scale complement can result from insane profile data
+ in which the total incoming edge counts in this module is
+ larger than the callee's entry count. The insane profile data
+ usually gets generated due to the following reasons:
+
+ 1) in multithreaded programs, when profile data is dumped
+ to gcda files in gcov_exit, some other threads are still running.
+ The profile counters are dumped in bottom up order (call graph).
+ The caller's BB counters may still be updated while the callee's
+ counter data is already saved to disk.
+
+ 2) Comdat functions: comdat functions' profile data are not
+ allocated in comdat. When a comdat callee function gets inlined
+ at some callsites after instrumentation, and the remaining calls
+ to this function resolves to a comdat copy in another module,
+ the profile counters for this function are split. This can
+ result in sum of incoming edge counts from this module being
+ larger than callee instance's entry count. */
+
+ if (scale_complement < 0 && flag_profile_correction)
+ scale_complement = 0;
+
orig_node->count =
orig_node->count * scale_complement / REG_BR_PROB_BASE;
for (cs = node->callees; cs; cs = cs->next_callee)
